Answer:
To find the price of 3 tons of concrete, we need to use a proportion:
If 2/3 ton of concrete costs $42, then 1 ton of concrete costs:
$42 ÷ (2/3) ton = $42 × (3/2) = $63
Therefore, 3 tons of concrete will cost:
$63 × 3 = $189
So Trey would need to pay $189 for 3 tons of concrete.